Final answer:
Secure attachment is the stable attachment style combination.
Step-by-step explanation:
The stable attachment style combination is secure attachment.
Secure attachment is the most common and considered the healthiest attachment style. In this attachment style, the child prefers the parent over a stranger and uses the parent as a secure base to explore the environment. They seek out the attachment figure in times of stress and are happy to see them when they return.
On the other hand, insecure attachment styles such as avoidant attachment and ambivalent-resistant attachment are not considered stable. Avoidant attachment is characterized by the child being unresponsive to the parent, not using the parent as a secure base, and not caring if the parent leaves. Ambivalent-resistant attachment is characterized by clingy behavior but rejecting the attachment figure's attempts to interact with them.